[PATCH] D28267: ELF: Round p_memsz of the PT_GNU_RELRO program header up to the page size.

[Peter Collingbourne via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL290986: ELF: Round p_memsz of the PT_GNU_RELRO program header up to the page size. (authored by pcc).

Changed prior to commit:
  https://reviews.llvm.org/D28267?vs=82992&id=83088#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D28267

Files:
  lld/trunk/ELF/Writer.cpp
  lld/trunk/test/ELF/basic-mips.s
  lld/trunk/test/ELF/basic-ppc.s


Index: lld/trunk/ELF/Writer.cpp
===================================================================
--- lld/trunk/ELF/Writer.cpp
+++ lld/trunk/ELF/Writer.cpp
@@ -1444,8 +1444,13 @@
     }
     if (P.p_type == PT_LOAD)
       P.p_align = Config->MaxPageSize;
-    else if (P.p_type == PT_GNU_RELRO)
+    else if (P.p_type == PT_GNU_RELRO) {
       P.p_align = 1;
+      // The glibc dynamic loader rounds the size down, so we need to round up
+      // to protect the last page. This is a no-op on FreeBSD which always
+      // rounds up.
+      P.p_memsz = alignTo(P.p_memsz, Config->MaxPageSize);
+    }
 
     // The TLS pointer goes after PT_TLS. At least glibc will align it,
     // so round up the size to make sure the offsets are correct.
Index: lld/trunk/test/ELF/basic-ppc.s
===================================================================
--- lld/trunk/test/ELF/basic-ppc.s
+++ lld/trunk/test/ELF/basic-ppc.s
@@ -295,7 +295,7 @@
 // CHECK-NEXT:     VirtualAddress: 0x2000
 // CHECK-NEXT:     PhysicalAddress: 0x2000
 // CHECK-NEXT:     FileSize: 48
-// CHECK-NEXT:     MemSize: 48
+// CHECK-NEXT:     MemSize: 4096
 // CHECK-NEXT:     Flags [ (0x4)
 // CHECK-NEXT:       PF_R (0x4)
 // CHECK-NEXT:     ]
Index: lld/trunk/test/ELF/basic-mips.s
===================================================================
--- lld/trunk/test/ELF/basic-mips.s
+++ lld/trunk/test/ELF/basic-mips.s
@@ -297,7 +297,7 @@
 # CHECK-NEXT:     VirtualAddress: 0x30000
 # CHECK-NEXT:     PhysicalAddress: 0x30000
 # CHECK-NEXT:     FileSize: 8
-# CHECK-NEXT:     MemSize: 8
+# CHECK-NEXT:     MemSize: 65536
 # CHECK-NEXT:     Flags [ (0x4)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:     ]


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